Alcohol beverage dispensing apparatus

ABSTRACT

A cooling system for a home beer dispensing apparatus has a mediated thermal bridge providing a bank of latent cooling capacity. The bridge may have a cavity filled with a cooling solution with at least one series of spaced apart heat exchange fins extending substantially along and interstitially into the cavity from at least one wall of the cavity so as to enhance heat transfer across the cavity. The bridge is arranged in thermal conducting relation through a cooling plate between a keg containing the beer and a Peltier thermoelectric cooling device adapted to cool the cooling solution by extracting heat therefrom to an active heat sink. A fan directs air flow horizontally along the fins of the sink and out the two lateral open sides of the heat sink. This prevents heat from rising in the apparatus and thereby affecting other system component parts. The cooling solution may comprise 5% by volume glycol and freezes at a temperature below that of water providing an improved thermal bank. The cooling plate has an electrical resistance heater mounted therein to maintain the temperature of beer in the keg adjacent a bottom portion thereof above the freezing temperature of the beer. The cooling system is economical in its space requirements and enhances the chilling of the beer to a desired serving temperature. The invention also provides a beer keg for such systems.

FIELD OF THE INVENTION

The present invention relates to a cooling system for use in an alcoholbeverage dispensing apparatus and in particular, relates to a coolingsystem having a mediated thermal bridge for use in a home beerdispensing apparatus. It further relates to the construction of acontainer, namely a beer keg, for use in such systems.

BACKGROUND OF THE INVENTION

Beer dispensing apparatus are known in the art for dispensing of draftbeer in taverns and the like. Typically, the beer is chilled prior tobeing dispensed by passing through a conical run of tube that passesthrough a chilled compartment containing ice and water. In someinstances the compartment is refrigerated. Such draft beer dispensersare utilized in taverns where the large volumes of beer are dispensedeveryday and the taverns have room to store such chillers. This is notthe case for a domestic or home beer dispensing apparatus that isadapted to sit on a countertop in a kitchen where space is at a premium.

Further, due to limited countertop space requirements, there still is aneed to chill or cool the beer in the dispensing apparatus to servingtemperatures in an optimal manner in spite of the limited space.Further, the quicker the beer is chilled to a desired servingtemperature, the more useful the beer dispenser is to the consumer.Hence improvements in heat transfer capabilities within the dispensingapparatus are important features.

Moreover, in a home beer dispenser, beer is typically drawn adjacent thebottom of the keg as this is usually the first region in the keg tochill. However, in the event the keg is left in the dispensing apparatusfor a period of time greater than that necessary to bring the beer downto a serving temperature near the freezing temperature of the beer, thebeer may freeze adjacent the bottom region of the keg preventing properdispensing of the beer.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an alcohol beverage,such as beer, dispensing apparatus having a cooling system that iseconomical in its space requirements and enhances the extraction of heatfrom the beer.

Another object of the present invention is to provide an alcoholbeverage dispensing apparatus having a cooling system which prevents thebeverage from freezing in the apparatus.

It is a further object of the present invention to provide a keg forcontaining an alcohol beverage which keg has a keg shell constructionthat is economical to manufacture and that is suitable for use in a homealcohol beverage dispensing system, preferably, a beer dispensingsystem.

The present invention relates to a cooling system for use with analcohol beverage dispensing apparatus where the cooling system has amediated thermal bridge having a banked latent cooling capacity providedby a cooling medium, preferably a solution of water and glycol,contained in a cavity in the thermal bridge. The thermal bridge isarranged in thermal conducting relation between a keg containing thealcohol beverage and a cooling device which acts as an active heat sink.Preferably the mediate thermal bridge is a fully intermediated bridge inwhich all of the heat is transferred from the alcohol beverage to thecooling device, including the active heat sink, through the thermalbridge.

In another aspect, the cooling system may also have a heat sink having aplurality of spaced apart heat exchange fins extending alongcorresponding spaced apart, preferably generally, horizontal planes.Preferably, the heat sink has a support wall from which the exchangefins extend to define two opposing lateral open sides and an open front.Means for directing air flow towards the open front of the heat sink areprovided whereby the horizontal extending fins and supporting walldirect the air flow generally horizontally or side wards along the finsand out the two lateral open sides of the heat sink. This prevents heatfrom rising making it more readily acceptable to mount other componentparts above the heat sink and thereby conserve on space. Alternatively,the horizontal flow of air may be directed inwardly from one of the twoopposing lateral open ends. Also, the heat sink may have only two opensides as contrasted to three open sides in the preferred embodiment.

Preferably, the cavity has a second wall, opposite to the one wall, thatsupports a second series of spaced apart heat exchange fins that extendalong and interstitially into the cavity in spaced apart relation withthe first series of spaced apart heat exchange fins so as to furtherpromote heat exchange through the cavity.

In yet a further aspect, the present invention relates to a coolingsystem for use with a alcohol beverage dispensing apparatus wherein thebeverage is contained in a container such as a keg and where a heater islocated adjacent the bottom portion of the keg in thermal conductingrelation therewith to prevent the beverage from freezing in theapparatus and specifically adjacent the internal bottom portion of thekeg.

Therefore, in accordance with one embodiment of the present inventionthere is provided a cooling system for cooling a keg containing analcohol beverage. The cooling system comprises a thermal bridge adaptedto contact a surface portion of the keg. The thermal bridge has areservoir or cavity filled with a cooling solution comprising a mixtureof water and glycol. The cooling system further comprises a coolingdevice adapted to chill the thermal bridge, including the coolingsolution in the reservoir, so as to produce a latent heat coolingcapacity in the thermal bridge for cooling the alcohol beveragecontained in the keg when the keg is mounted in heat transfer relationwith the thermal bridge.

In accordance with another embodiment of the present invention there isprovided a cooling system for cooling a keg containing an alcoholbeverage. The cooling system comprises a thermal bridge adapted tocontact a surface portion of the keg. The thermal bridge has a cavityfilled with a cooling solution. The cavity has a first series of spaceapart heat exchange fins extending substantially along andinterstitially into the cavity from at least one wall of the cavity. Thecooling system further comprises a cooling device adapted to chill thethermal bridge and extract heat through the thermal bridge from thealcohol beverage contained in the keg when the keg is mounted in heattransfer relation with the thermal bridge.

Preferably, the first and second series of heat exchange fins extendinto the cavity in parallel interleaved relation. Also, the cavity isformed of a top portion and a bottom portion that are secured togetherin sealed relation. The top portion has a cooling plate that is adaptedto contact the keg in heat exchange relation. The first series of finsextend into the cavity from the top portion. The bottom portion supportsthe second series of fins to extend into the cavity therefrom.

In accordance with another embodiment of the present invention there isprovided a cooling system for cooling a keg containing an alcoholbeverage, which system comprises a cooling plate adapted to receive abottom portion of the keg in heat transfer relation therewith, andheating means mounted with the cooling plate adapted to maintain thetemperature of beverage in the keg adjacent the bottom portion of thekeg above the freezing temperature of the beverage.

Preferably, the heating means or heater conducts sufficient heat energyinto the base of the keg to provide an insulated layer of beer adjacentthe bottom of the keg where the beer is dispensed from the keg. Theheater is preferably an electrical resistance heating element located inthe cooling plate of the cooling system. Additionally, a temperaturecontroller may be adapted to sense the temperature adjacent the bottomregion of the keg and when the sensed temperature falls below apredetermined temperature where the beer may freeze, the temperaturecontroller energizes the heater to warm the beer until the sensedtemperature rises above the predetermined temperature.

The cooling solution preferably comprises 5% by volume glycol andfreezes at a temperature below that of water providing an improvedthermal bank. Further the cooling solution may contain anti-corrodingparticles to prevent or reduce the occurrence of corrosion in thethermal bridge. Preferably, the cooling solution is cooled to atemperature that forms ice. Preferably, the cooling device furtherincludes an active heat sink adapted to remove heat produced by thecooling system as the cooling system cools the thermal bridge. Theactive heat sink is also adapted to dissipate heat transferred throughthe thermal bridge from the alcohol beverage in the keg.

In accordance with yet another aspect of the present invention there isprovided a keg suitable for containing an alcohol beverage. The kegcomprises two keg half shells each identically formed to have an endwall portion and side walls extending from the end wall portion thatterminate in a continuous side wall edge portion. The two keg halfshells have their respective side wall edge portions placed in abuttingrelation with one another and joined together to form the keg.

An advantage of the present invention is that forming the keg from twoidentical shells provides a manufacturing cost reduction.

Preferably, the end wall portion of each half shell is formed with araised annular collar and a face plate extending across the collar tonormally close the collar. The face plate of one of the two keg halfshells is adapted to engage a cooling plate of a dispensing apparatus inheat transfer relation therewith and the other of the two keg halfshells is at least partially removed to form an aperture for receiving avalve and spear for filling into and dispensing from the keg thebeverage. This preferred construction of the keg renders the kegoperable for use in a home beverage dispensing system such as, forexample, a beer dispensing apparatus.

Preferably, the side walls of the two keg half shells comprise acontinuous substantially cylindrical wall extending substantially normalfrom the end wall portion. The side wall edge portions of eachcylindrical side wall preferably abut each other along a common planethat passes through a center of the keg. Preferably, the keg half shellsare joined by a weld to form the keg.

By substantially cylindrical wall it is meant a wall that resembles acylinder either having a constant radius along its length or asubstantially constant radius along its length. It is envisaged that theradius of the keg may be slightly large toward the keg center to providea center bulge.

Preferably the alcohol beverage is beer and the cooling system isutilized in a home beer dispensing apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the nature and objects of the presentinvention reference may be had to the accompanying diagrammatic drawingsin which:

FIG. 1 is a front elevation view of a home beer dispensing apparatus inaccordance with the present invention;

FIG. 2 is a side elevation view of the home beer dispensing apparatus;

FIG. 3 is an enlarged perspective view of the cooling system for thebeer keg housed in the home beer dispensing apparatus illustrating thethermal bridge and its cavity and the keg of the present inventionmounted on the cooling plate;

FIG. 4 is a perspective view of the top portion of the thermal bridge;

FIG. 5 is a perspective view of the base portion of the thermal bridgeshowing the orientation of the base portion reversed relative to theorientation of the top portion shown in FIG. 4;

FIG. 6 is a cross sectional view of the cavity of the thermal bridgetaken along section line VI-VI of FIG. 3;

FIG. 7 is a plan view of the heat sink and fan showing the horizontalair flow across the heat exchanger;

FIG. 8 is a sectional view of the keg of the present invention showingtwo keg shells prior to joining; and

FIG. 9 is a cross-sectional view of a formed keg having a dispensingspear within the keg and resting on a cooling plate for cooling thecontents of the keg.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1 and 2 there is shown a home beer dispensingapparatus, appliance or unit 10. The dispensing apparatus 10 isprimarily intended for use in domestic kitchens but may also be used inutility rooms, garages, domestic bars, caravans etc. While the preferredembodiment relates to dispensing beer, alternatively carbonatedsolutions or other alcohol beverages may be dispensed by apparatus 10.

The home beer dispensing apparatus 10 has a front wall 12 and adispensing tap 14 protruding forward of the front wall 12. A drip tray16 also protrudes forward of the front wall 12 and is adapted to supportan open glass container 18 below the dispensing tap 14. The home beerdispensing apparatus 10 further has a base 21 adapted to rest on acounter top. The front wall 12 is an extension of two pivoting sidewalls 20 which may be moved between closed and open positions to allowthe keg 22 (see FIG. 2 in broken lines) to be inserted into the housingof the home beer dispensing apparatus 10.

The housing of the home beer dispensing apparatus 10 further includes atop wall 24 and a rear wall 26. The rear wall 26 has a grill 30 thatpermits for air circulation within the home beer dispensing apparatus10. An electrical cord 32 extends through the rear wall 26 of theapparatus 10 to provide a connection into a main electrical supply tosupply electrical power to the electrical components housed within theunit 10. Alternatively, a 12 Volt DC supply input may be used.

The dispensing apparatus 10 has a cooling system 34 located behind andbelow keg 22 that is adapted to cool beer 70 in keg 22 when keg 22 isplaced into dispensing apparatus 10. The dispensing apparatus 10 alsodispenses the beer by providing and using a pressurized air supply (notshown).

Referring to FIG. 3, the cooling system 34 is utilized to keep the beerin keg 22 at an ideal serving temperature for drinking.

The cooling system 34 has a Peltier thermoelectric device 36 thatproduces the necessary cooling effect. When a voltage is applied to thePeltier device 36 across leads 38 a thermal differential is generatedacross the Peltier device 36 which is used to cool a mediate thermalbridge 40. The Peltier thermoelectric device 36 provides a lowcontinuous cooling rate along its cold side portion 60 to aluminum block42 mounted to rear wall 70 of the thermal bridge 40.

To maximize the cooling power of the Peltier device 36, the hot sideportion 44 of the Peltier device 36 is cooled by an active heat sink 46coupled to the hot side portion 44. The heat sink 46, as seen in FIGS. 3and 7, has a series of spaced apart horizontally extending fins or ribs48 which extend along corresponding horizontal planes and across whichair flows to cool the heat sink 46. The heat sink has a supporting wall47 from which the heat exchange fins 48 extend to define two opposinglateral open sides 51, 53 and an open front 55.

A fan 50 is coupled to heat sink 46 against the open front 55 to blowambient air passing through the grill 30 over the fins 48, out opensides 51, 53 and thereby make the heat sink 46 active. The fan 48 ispositioned such that air is blown directly onto the face of the heatsink 46 as indicated by arrows 52 so as to maximize the turbulent airflow and the resultant heat dissipation from the heat sink occurs as theair flows horizontally out of the heat sink 46 between and across fins48 as exemplified by air flow arrows 54. In FIG. 7, a plan view of theheat sink 46 and fan 50 further illustrates the air flow 52 and 54entering open front 55 and exiting opposing open sides 51, 53.

While vertical air flow across fins of a heat sink is considered a usualair flow path that takes advantage of the chimney effect of rising heat,the area within the dispensing apparatus 10 is filled with othercomponent parts for the unit such as, for example, air pressure devices,the dispense tap, and possibly electronic hardware that should be keptat ambient temperature to operate effectively. In this environment, thechimney effect of a heat sink is detrimental to the operation andfitting of component parts in the fixed housing space of apparatus 10and the operation of the horizontal air flow across heat sink 48 isbeneficial.

As shown in FIG. 1, the dispensing apparatus 10 has the grill 30 locatedin it's rear wall 26 through which air flow 52 into the apparatus 10 isdrawn in by fan 50 and air flow out at 54 is achieved by horizontalextending fins 48 of the heat sink. The exit air flow 54 from grill 30is shown to be above and below intake air flow 52 in FIG. 1; however, inpractice, the exiting air flow 54 is more to the side of input air flow52. Hence the horizontal orientation of fins 48 of heat sink 46 resultin an air flow in a direction away from component parts located abovethe heat sink 46 within dispensing apparatus 10.

As mentioned, the cold side wall portion 60 of the Peltier device 36 isattached to the thermal bridge 40 through aluminum block 42. In thepreferred embodiment, the thermal bridge 40 is aluminum and has aninternal reservoir cavity 62 formed therein. The cavity 62 contains acooling solution 66 (see FIG. 6) of water and, preferably 5%, glycol.The cavity 62 provides a cooling bank and is cooled by Peltier device36.

The bridge 40 has a cooling plate 64 upon which the keg 22 is locatedwithin the dispensing apparatus 10. The cooling plate 64 is locatedunderneath the keg 22 so that the weight of the keg 22 is applied to theinterface between the keg 22 and the cooling plate 64 thereby improvingconductivity. The cooling at the bottom portion 68 of the keg 22 alsoensures that beer to be drawn first, from the bottom of the keg, iscooled first. Cooling at the bottom portion 68 also permits insulation(not shown) around the top of the keg 22 to be thinner and lesseffective to allow cold air created inside the dispensing apparatus 10to sink to the bottom portion 68.

It should be understood that the rate of cooling across the interfacebetween keg 22 and cooling plate 64 is proportional to both theeffectiveness of the interface contact between the two and thetemperature differential between beer 69 housed in keg 22 and coolingplate 64.

Referring to FIGS. 4, 5 and 6, the assembly for the mediated thermalbridge 40 is shown. The mediated thermal bridge comprises cavity 62filled with the cooling solution 66 (FIG. 6) comprising a mixture ofwater and 5% glycol. This mixture improves cooling rate, whilst ensuringthat the beer does not actually freeze. The freezing point of the waterin the ice store is reduced by a couple of degrees by the addition ofthe small amount of antifreeze or glycol. The cooling plate is now at 0°C. rather than 2° C. and the cooling rate of the beer increased. Thecooling solution 66 effectively provides a bank of latent coolingcapacity through cooling plate 64 to keg 22.

The ice store cavity 62 of the thermal bridge 40 preferably contains 1.5liters of water and glycol mixture (5% glycol) and is permanentlysealed. The 5% glycol allows freezing at −2° C. The glycol water mixtureeffectively increases the differential temperature between the beer andthe cooling plate. The ice store mixture may also contain corrosioninhibitors.

The thermal bridge 40 comprises a top portion 72 (see FIG. 4) comprisinga top wall 74 and the cooling plate 64 beveled to receive the beveledbottom 68 of the keg 22. The top wall 74 has a series of spaced apartelongated fins 76 extending along and outwardly therefrom andinterstitially into the cavity 62. The top portion 72 is adapted tosealingly engage side walls 78 of cavity bottom portion 80 (see FIG. 5).Bottom portion 80 has a base wall 82 and a series of spaced apartelongated fins 84 that extend along and outwardly from base wall 82 andinterstitially into cavity 62. Part 80 is filled with cooling solution66 (FIG. 6) and part 72 is sealed to part 80 to form cavity 62. Fins 76of top portion 72 are inter spaced with and between fins 84 of lowerportion 80 to provide an interleaved relationship when the thermalbridge 40 is assembled. The cooling solution 66 is positioned withincavity 62 located between fins 76 and 80 (see FIG. 6). The coolingsolution 66 boosts the cooling effect in cavity 62 between fins 76 and84 due to additional latent heat capacity because water in the solutionis frozen when sufficient cooling is provided by the Peltier device 36.The frozen water is a thermal bank. When the keg 22 is put on coolingplate 64, the latent cooling, or thermal bank provides ability to drawheat out of the keg 22 more readily. The latency is built in to thecooling cycle in course of operating the dispensing apparatus 10.

The utilization of the ice storage cavity 62 of the thermal bridge 40 inthe cooling system 34 boosts the ability of the cooling system 34 tolower the temperature of the beer 70 in the keg 22. The bridge 40decreases the cooling time for the beer to a desired serving temperatureoffering benefits to the user. This is achieved by means of an ice storelocated in the aluminum block cavity 62. The solution is frozen to formice by the Peltier device 36 once a keg 22 of beer is cooled inpreparation for the next keg. The latent energy required in the phasechange from water to ice is considerable. About 2 kg of water, whenfrozen, has the capacity to absorb enough energy to cool 6 kg of waterby 20° C. When a new keg 22 is inserted into the dispensing apparatus10, the new keg cools much quicker than by the use of a Peltier deviceand cooling fan alone.

Further, a good thermal contacting relation between the cooling solution66 and the aluminum block cavity 62 provided by interleaved fins 76 and84 ensures both rapid freezing of the ice and rapid thawing when coolingbeer. This is achieved by using the elongated finned internal surfacesof the fins 76 and 84 in a manner similar to a heat sink.

An ice store of cooling solution 66 is preferably at 0° C. when coolingthe beer. However, there is a temperature gradient through the aluminumblock cavity 62 and the ice store or cooling solution 66, when cooling,is colder than the cooling plate 64 by as much as 2 or 3° C. Thedifferential between beer and cooling plate 64 temperatures is less thanit could be if the cooling plate were at 0° C. and cooling would beslower.

The Peltier unit 36 preferably is a 50W or 72W rated device. The Peltierunit 36 is preferably clamped between the heat sink 46 and thermalbridge 40 by using two stainless steel bolts (not shown).

Referring to FIG. 3, the cooling plate 64 has mounted therein anelectrical resistance heater or heating element 45. Heating element 45is connected to a source of electrical supply (not shown). Heatingelement 45 is mounted in heat transfer relation with the keg 22 andmaintains the temperature of beer 69 adjacent the bottom portion 68 ofthe keg 22 above freezing temperature of the beer 69. The cooling system34 further includes a temperature sensor 63 adapted to contact the keg22 adjacent the bottom portion 68 for sensing temperature related to thetemperature of the beer 69 in the keg 22. The cooling system 34 has atemperature controller 65 responsive to the temperature sensed by thetemperature sensor 63 to energize the heater 45 to transfer heat intothe bottom portion 68 of the keg 22 to maintain the temperature of thebeer 69 above its freezing temperature. The temperature sensor andcontroller may comprise a bi-metal thermostat in circuit with theheating element 45 which cycles the heating element 45 on and off.Alternatively, the temperature sensor may comprise a thermistorconnected with a control circuit to cycle the heating element on andoff.

The Peltier device 36 and fan 50 supply voltages are controlled so thatwhen the beer is finally cooled to the desired serving temperature alower rate of energy extraction is provided to avoid freezing the beerand to reduce energy consumption and noise. The use of Peltier device 36and fan 50 preferably limits the cooling power to, at most, 50 W andmore typically 30 W. The cooling of a 6 liter keg of beer from 23° C. to3° C. by the Peltier device 36 and fan 50 alone typically takes 8 to 20hours. The material of the keg 22 has an effect on this cooling time.

The rating of the heat sink 46 and fan 50 is better than 0.25° C./W. Atan ambient temperature of 22° C., the heat sink 46 temperature measuredadjacent to the hot side 44 of the Peltier device 36 is preferably notbe above 35° C. The heat sink 46 is preferably made from extrudedAluminum. It need not be coated. The fan 50 preferably provides 29 cfm(cubic feet per minute) at 12V supply. The fan is capable of starting at6V.

The mediate thermal bridge 40 connects the Peltier device 36 cold sidewall portion 60 to the cooling plate 64 underneath the keg 22. Thetemperature gradient between these two points preferably does not exceed3° C. at 40 W flow.

The mediate thermal bridge 40 is preferably manufactured from castaluminum alloy LM 20. This material has been chosen for its thermalconductive properties.

The cooling plate 64 to keg 22 interface is preferably matched to theform of a keg pressurized at 1.5 bar. The temperature differentialbetween cooling plate 64 and the keg bottom surface 68 (which is at 3°)shall be <3° C. (i.e. the cooling plate 64 should be at a temperature of0° C. under these conditions).

While the preferred embodiments described in relation to the drawingsare for a thermal bridge having a cavity located in heat transferrelation with the keg below the bottom portion of the keg, it should beunderstood that the thermal bridge may be located in other locations inheat transfer relation with the keg. One such other location, forexample, is to locate the thermal bridge beside the keg in heat transferrelation to the side wall of the keg.

Referring to FIGS. 1 to 3, the cooling of the keg 22 within the beerdispensing apparatus 10 is accomplished by a the cooling system 23having a cooling plate 64 having a cooling surface 172 that is inmechanical and heat transfer contacting relation with the bottom portion140 of the keg 22.

The dispensing apparatus 10 also fills and dispenses beer into and outof the keg 22 through a valve 142 and spear 144 as best seen in FIG. 4.The keg 22 preferably includes a bag (not shown) for holding the beerwithin the keg 22 and into which the spear 144 extends.

Referring to FIGS. 8 and 9, the keg 22 of the present invention is shownin more detail.

In accordance with this aspect of the present invention, the keg 22 isformed from two keg half shells 150. Each of the keg half shells 150 areidentically formed by deep drawing of a material selected from the groupconsisting of steel, stainless steel, and aluminum.

The keg half shells 150 each have an end wall portion 152 andsubstantially cylindrical side wall 154. The cylindrical side wall 154is shown in FIG. 8 to comprise a wall having two different radii r₁ andr₂ where r₂ is greater than r₁ to provide a bulge 160 at the center 162of keg 22. In FIGS. 4 and 5 the cylindrical side wall 154 of each keghalf shell 150 has a uniform radius r₃. As shown in FIGS. 3 to 5, thesubstantially cylindrical side walls 54 extend substantially normal orperpendicular to the end wall portion 152. The end wall portions 152 ofthe keg shells 150 each have a generally concave curvature 156 relativeto the cylindrical side wall 154 and interior of the keg 22.

Each end wall portion 152 is formed with a raised annular collar 164 andflat face plate 166 extending across the collar 164 to normally closethe collar 164. While only one face plate 166 is shown in the bottomshelf half 150 in the drawings, it should be understood that keg halfshells 154 are each formed with a face plate 166. The collars 164strengthen the keg. The bottom face plate 166 of the two keg half shells150 is adapted to engage the cooling plate 64 in heat transfer relationtherewith. The other or top face plate (not shown) of the two keg halfshells 150 is at least partially removed to form an aperture 180 as seenin FIG. 8. Aperture 180 is adapted to receive valve 142 (see FIG. 9) andhollow spear 144 shown extending into the keg 22. The valve 142 andspear 144 provide means for filling keg 22 with beer and for dispensingbeer from keg 22 through tap 114 (FIG. 1).

Each end wall portion 152 has an annular rim 151 shown curved in FIGS. 3and 9 and as a ridge in FIG. 8. The annular rim 151 extends about theperiphery of end wall portion 152 adjacent the cylindrical wall 154. Therim 151 is adapted to support a chime (not shown) for orientating thekeg 22 in the home beer dispensing apparatus 10.

The cylindrical side wall 154 terminates in a continuous side wall edgeportion 157. The two keg half shells 150 have their respective side walledge portions 157 placed in abutting relation with one another along acommon plane 159 that passes through the center of the keg 22. The keghalf shells 150 are joined together by a weld 161 along the abuttingside wall edge portions 157 to form the keg 22.

The formation of the keg of the present invention has the advantage ofutilizing a simple embossed design that produces a centering bottom faceplate 166 for supporting the keg 22 in a heat transfer seatedarrangement with a cooling plate 64 and a centering aperture 180 forreceiving the valve 142 and the spear 144 for filling into anddispensing beer from the keg 22.

Although not shown in the drawings, a closed cell foam membrane islocated below the cooling fluid. As the cooling fluid expands andcontracts the foam collapses ensuring the upper surface is alwayscontacted. This is particularly important when a phase change occurs. Italso provides for better heat transfer by allowing the cavity to befilled up with the cooling fluid which is in contact with the uppercooling face without having to allow for expansion head space.

It will be appreciated that beer is the beverage of choice to bedispensed using the present invention but other, especially, carbonatedbeverages could also benefit from using the present invention.

1. A cooling system for cooling a keg containing an alcohol beverage,the cooling system comprising: a thermal bridge adapted to contact asurface portion of the keg and having a cavity filled with a coolingsolution; and a cooling device adapted to chill the thermal bridge,including the cooling solution in the cavity for extracting heat fromand for cooling the alcoholic beverage contained in the keg when the kegis mounted in heat transfer relation with the thermal bridge.
 2. Acooling system according to claim 1 wherein the cooling solution ischilled to the extent it has a latent heat cooling capacity.
 3. A systemaccording to claim 1 or 2 wherein said cooling solution is a mixture ofwater and glycol.
 4. A cooling system for cooling a keg containing analcohol beverage, the cooling system comprising: a thermal bridgeadapted to contact a surface portion of the keg and the thermal bridgehaving a cavity filled with a cooling solution comprising a mixture ofwater and glycol; and a cooling device adapted to chill the thermalbridge, including the cooling solution in the cavity, so as to produce alatent heat cooling capacity in the thermal bridge for cooling thealcohol beverage contained in the keg when the keg is mounted in heattransfer relation with the thermal bridge.
 5. The cooling system ofclaim 4 wherein the cooling solution comprises 5% by volume glycol. 6.The cooling system of claim 4 wherein the cooling solution furthercontains a corrosion inhibitor.
 7. The cooling system of claim 4 whereinthe solution is cooled to form ice.
 8. The cooling system of claim 4wherein the cooling device has a Peltier thermoelectric cooling unitthat has a cool surface portion in heat transfer contact with thethermal bridge and that has a hot surface portion in heat transfercontact with a heat sink.
 9. The cooling system of claim 8 wherein thecooling device further includes a fan for directing air flow across theheat sink.
 10. The cooling system of claim 4 wherein the thermal bridgecomprises a cooling plate adapted to contact a bottom surface portion ofthe keg.
 11. The cooling system of claim 4 wherein the cooling devicefurther includes an active heat sink adapted to remove heat from thethermal bridge and to dissipate heat transferred through the thermalbridge from the alcohol beverage in the keg.
 12. A home beer dispensingapparatus having a cooling system for cooling a keg containing beer, thecooling system comprising: a thermal bridge adapted to contact a surfaceportion of the keg and the thermal bridge having a reservoir filled witha cooling solution comprising a mixture of water and glycol; and, acooling device adapted to chill the thermal bridge, including thecooling solution in the reservoir, so as to produce a latent heatcooling capacity in the thermal bridge for cooling the beer contained inthe keg when the keg is mounted in heat transfer relation with thethermal bridge.
 13. The dispensing apparatus of claim 12 wherein thecooling solution comprises 5% by volume glycol.
 14. The dispensingapparatus of claim 12 wherein the cooling solution further contains acorrosion inhibitor.
 15. The dispensing apparatus of claim 12 whereinthe solution is cooled to form ice.
 16. The dispensing apparatus ofclaim 12 wherein the cooling device has a Peltier thermoelectric coolingunit that has a cool surface portion in heat transfer contact with thethermal bridge and that has a hot surface portion in heat transfercontact with a heat sink.
 17. The dispensing apparatus of claim 16wherein the cooling device further includes a fan for directing air flowacross the heat sink.
 18. The dispensing apparatus of claim 12 whereinthe thermal bridge comprises a cooling plate adapted to contact a bottomsurface portion of the keg.
 19. The dispensing apparatus of claim 12wherein the cooling device further includes an active heat sink adaptedto remove heat from the thermal bridge and to dissipate heat transferredthrough the thermal bridge from the beer in the keg.
 20. A coolingsystem for cooling a keg containing an alcohol beverage, the coolingsystem comprising: a thermal bridge adapted to contact a surface portionof the keg and the thermal bridge having a cavity filled with a coolingsolution, the cavity has a first series of spaced apart heat exchangefins extending substantially along and interstitially into the cavityfrom at least one wall of the cavity; and, a cooling device adapted tochill the thermal bridge and extract heat from the alcohol beveragecontained in the keg when the keg is mounted in heat transfer relationwith the thermal bridge.
 21. The cooling system of claim 20 wherein thecooling system is a solution of glycol in water.
 22. The cooling systemof claim 20 wherein the cavity has a second wall, opposite to the onewall, that supports a second series of spaced apart heat exchange finsthat extend along and interstitially into the cavity in spaced apartrelation with the first series of spaced apart heat exchange fins, andthe cooing solution filling the space between the first and secondseries of heat exchange fins.
 23. The cooling system of claim 22 wherethe first and second series of heat exchange fins extend into the cavityis parallel interleaved relation.
 24. The cooling system of claim 22wherein the cavity is formed of a top portion and a bottom portion thatare secured together in sealed relation, the top portion comprising acooling plate the is adapted to contact the keg in heat transferrelation and the first series of fins extending into the cavity from thetop portion, and the bottom portion supporting the second series of finsto extend into the cavity.
 25. The cooling system of claim 22 whereinthe cooling solution comprises 5% by volume glycol.
 26. The coolingsystem of claim 22 wherein the cooling solution is cooled to form ice.27. The cooling system of claim 22 wherein the cooling device comprisesa Peltier thermoelectric cooling unit that has a cool surface portion inheat transfer contact with the thermal bridge and that has a hot surfaceportion in heat transfer contact with a heat sink.
 28. The coolingsystem of claim 27 wherein the cooling system further includes a fan fordirecting air flow across the heat sink.
 29. A home beer dispensingapparatus having a cooling system for cooling a keg containing beer, thecooling system comprising: a thermal bridge adapted to contact a surfaceportion of the keg and the thermal bridge having a cavity filled with acooling solution, the cavity has a first series of spaced apart heatexchange fins extending substantially along and interstitially into thecavity from at least one wall of the cavity; and, a cooling deviceadapted to chill the thermal bridge and extract heat from the beercontained in the keg when the keg is mounted in heat transfer relationwith the thermal bridge.
 30. The home beer dispensing apparatus of claim29 wherein the cavity has a second wall, opposite to the one wall, thatsupports a second series of spaced apart heat exchange fins that extendalong and interstitially into the cavity in spaced apart relation withthe first series of spaced apart heat exchange fins, and the cooingsolution filling the space between the first and second series of heatexchange fins.
 31. The home beer dispensing apparatus of claim 30wherein the first and second series of heat exchange fins extend intothe cavity is parallel interleaved relation.
 32. The home beerdispensing apparatus of claim 30 wherein the cavity is formed of a topportion and a bottom portion that are secured together in sealedrelation, the top portion comprising a cooling plate the is adapted tocontact the keg in heat transfer relation and the first series of finsextending into the cavity from the top portion, and the bottom portionsupporting the second series of fins to extend into the cavity.
 33. Thehome beer dispensing apparatus of claim 30 wherein the cooling solutioncomprises 5% by volume glycol.
 34. The home beer dispensing apparatus ofclaim 30 wherein the cooling solution is cooled to form ice.
 35. Thehome beer dispensing apparatus of claim 30 wherein the cooling devicecomprises a Peltier thermoelectric cooling unit that has a cool surfaceportion in heat transfer contact with the thermal bridge and that has ahot surface portion in heat transfer contact with a heat sink.
 36. Thehome beer dispensing apparatus of claim 35 wherein the cooling systemfurther includes a fan for directing air flow across the heat sink. 37.A cooling system for cooling a keg containing an alcohol beverage, thecooling system comprising: a heat sink having a plurality of spacedapart heat exchange fins extending along corresponding spaced apartnon-vertical planes.
 38. The cooling system of claim 37 wherein the heatsink has at least one supporting wall from which the heat exchange finsextend to define at least two open sides, one of which is lateral andmeans for directing air flow towards one of the open sides along theheat exchange fins and out the other open side whereby the fins and atleast one supporting wall direct the air flow along the fins and out thelateral open side of the heat sink.
 39. A cooling system for cooling akeg containing an alcohol beverage, the cooling system comprising: aheat sink having a plurality of spaced apart heat exchange finsextending along corresponding spaced apart horizontal planes.
 40. Thecooling system of claim 39 wherein the heat sink has at least onesupporting wall from which the heat exchange fins extend to define atleast two open sides, and means for directing air flow towards one ofthe open sides along the heat exchange fins and out the other open sidewhereby the horizontal extending fins and at least one supporting walldirect the air flow horizontally along the fins.
 41. The cooling systemof claim 39 wherein the heat sink has a supporting wall from which theheat exchange fins extend to define two opposing lateral open sides andan open front, and means for directing air flow towards the open frontof the heat sink whereby the horizontal extending fins and supportingwall direct the air flow horizontally along the fins and out the twolateral open sides of the heat sink.
 42. The cooling system of claim 41wherein the means for directing air flow comprises a fan mounteddirectly to the open front of the heat sink.
 43. The cooling system ofclaim 42 further including a Peltier thermoelectric cooling unit mountedto an outside surface of the supporting wall of the heat sink and beingadapted to be mounted in heat transfer relation with the keg forenhancing the extraction of heat from the beverage contained in the kegtherethrough for dissipation from the heat sink.
 44. The cooling systemof claim 43 further including a cooling plate in heat transfer relationwith the Peltier thermoelectric cooling unit and a bottom surfaceportion of the keg.
 45. A home beer dispensing apparatus having acooling system for cooling a keg containing beer, the cooling systemcomprising: a heat sink having a plurality of spaced apart heat exchangefins extending along corresponding spaced apart horizontal planes. 46.The home beer dispensing apparatus of claim 45 wherein the heat sink hasat least one supporting wall from which the heat exchange fins extend todefine at least two open sides, and means for directing air flow towardsone of the open sides along the heat exchange fins and out the otheropen side whereby the horizontal extending fins and at least onesupporting wall direct the air flow horizontally along the fins.
 47. Thehome beer dispensing apparatus of claim 45 wherein the heat sink has asupporting wall from which the heat exchange fins extend to define twoopposing lateral open sides and an open front, and means for directingair flow towards the open front of the heat sink whereby the horizontalextending fins and supporting wall direct the air flow horizontallyalong the fins and out the two lateral open sides of the heat sink. 48.The home beer dispensing apparatus of claim 47 wherein the means fordirecting air flow comprises a fan mounted directly to the open front ofthe heat sink.
 49. The home beer dispensing apparatus of claim 47wherein the cooling system further includes a Peltier thermoelectriccooling unit mounted to an outside surface of the supporting wall of theheat sink and being adapted to be mounted in heat transfer relation withthe keg for enhancing the extraction of heat from the beer contained inthe keg therethrough for dissipation from the heat sink.
 50. The homebeer dispensing apparatus of claim 49 wherein the cooling system furtherincludes a cooling plate in heat transfer relation with the Peltierthermoelectric cooling unit and a bottom surface portion of the keg. 51.The home beer dispensing apparatus of claim 47 wherein the dispensingapparatus contains at least one grill through which ambient air is drawninto the apparatus across the open front of the heat sink and warmed airis directed by the heat exchange fins horizontally out of the apparatusthrough the at least one grill.
 52. The cooling system of claim 10 and24 wherein a heater is mounted with the cooling plate and adapted tomaintain the temperature of beverage in the keg adjacent the bottomportion of the keg above freezing temperature of the beverage.
 53. Thecooling system of claim 52 wherein the heater comprises an electricalresistance heater mounted in the cooling plate.
 54. The cooling systemof claim 53 further including a temperature sensor adapted to contactthe keg adjacent the bottom portion of the keg for sensing temperaturerelated to the temperature of the beverage in the keg, and a temperaturecontroller responsive to the temperature sensed by the temperaturesensor to energize the heater to transfer heat into the bottom portionof the keg and the beverage so as to maintain the temperature of thebeverage above its freezing temperature.
 55. The home beer dispensingapparatus of claim 10, 18, 44 or 50 is a heater mounted with the coolingplate and adapted to maintain the temperature of beer in the kegadjacent the bottom portion of the keg above freezing temperature of thebeer.
 56. The apparatus of claim 55 wherein the heater comprises anelectrical resistance heater mounted in the cooling plate.
 57. Theapparatus of claim 56 which further includes a temperature sensoradapted to contact the keg adjacent the bottom portion of the keg forsensing temperature related to the temperature of the beer in the keg,and a temperature controller responsive to the temperature sensed by thetemperature sensor to energize the heater to transfer heat into thebottom portion of the keg and the beer so as to maintain the temperatureof the beer above its freezing temperature.
 58. A cooling system forcooling a keg containing an alcohol beverage, the cooling systemcomprising: a cooling plate adapted to receive a bottom portion of thekeg in heat transfer relation therewith; and a heater mounted with thecooling plate adapted to maintain the temperature of beverage in the kegadjacent the bottom portion of the keg above freezing temperature of thebeverage.
 59. The cooling system of claim 58 wherein the heatercomprises an electrical resistance heater mounted in the cooling plate.60. The cooling system of claim 59 further including a temperaturesensor adapted to contact the keg adjacent the bottom portion of the kegfor sensing temperature related to the temperature of the beverage inthe keg, and a temperature controller responsive to the temperaturesensed by the temperature sensor to energize the heater to transfer heatinto the bottom portion of the keg and the beverage so as to maintainthe temperature of the beverage above its freezing temperature.
 61. Thecooling system of claim 59 further including a Peltier thermoelectriccooling unit mounted in heat transfer relation with the cooling platefor enhancing the extraction of heat from the beer contained in the keg.62. A home beer dispensing apparatus having a cooling system for coolinga keg containing beer, the cooling system comprising: a cooling plateadapted to receive a bottom portion of the keg in heat transfer relationtherewith; and a heater mounted with the cooling plate adapted tomaintain the temperature of beer in the keg adjacent the bottom portionof the keg above freezing temperature of the beer.
 63. The apparatus ofclaim 62 wherein the heater comprises an electrical resistance heatermounted in the cooling plate.
 64. The apparatus of claim 63 furtherincluding a temperature sensor adapted to contact the keg adjacent thebottom portion of the keg for sensing temperature related to thetemperature of the beer in the keg, and a temperature controllerresponsive to the temperature sensed by the temperature sensor toenergize the heater to transfer heat into the bottom portion of the kegand the beer so as to maintain the temperature of the beer above itsfreezing temperature.
 65. The apparatus of claim 63 further including aPeltier thermoelectric cooling unit mounted in heat transfer relationwith the cooling plate for enhancing the extraction of heat from thebeer contained in the keg.
 66. A keg suitable for containing an alcoholbeverage, the keg comprising two keg half shells each identically formedto have an end wall portion and side walls extending from the end wallportion that terminates in a continuous side wall edge portion, and thetwo keg half shells having their respective side wall edge portionsplaced in abutting relation with one another and joined together to formthe keg.
 67. The keg of claim 66 wherein the end wall portion of eachhalf shell is formed with a raised annular collar and a face plateextending across the collar to normally close the collar.
 68. The keg ofclaim 67 wherein the face plate of one of the two keg half shells isadapted to engage a cooling plate in heat transfer relation therewithand the other face plate of the two keg half shells is at leastpartially removed to form an aperture for receiving a valve and spearfor filling into and dispensing from the keg the beverage.
 69. The kegof claim 68 wherein the end wall portion of each keg shell has anannular rim extending about the periphery of the end wall portion andadjacent to the cylindrical wall.
 70. The keg of claim 69 wherein therim is adapted to support a chime for orientating the keg in a home beerdispensing apparatus.
 71. The keg of claim 69 wherein the end wallportions of the kegs each have a concave curvature relative to the sidewalls and interior of the keg.
 72. The keg of claim 66 wherein each ofthe keg half shells are formed by deep drawing of a material selectedfrom the group consisting of steel, stainless steel, and aluminum. 73.The keg of claim 66 wherein the side wall edge portions are joined by aweld.
 74. The keg of claim 66 wherein the side walls comprise acontinuous cylindrical wall and the side wall edge portions of eachcylindrical side wall abut each other along a common plane that passesthrough a center of the keg.
 75. The keg of claim 74 wherein the sidewall edge portions are joined by a weld.
 76. The keg of claim 74 whereinthe end wall portion of each half shell is formed with a raised annularcollar and a face plate extending across the collar to normally closethe collar.
 77. The keg of claim 76 wherein the face plate of one of thetwo keg half shells is adapted to engage a cooling plate in heattransfer relation therewith and the other face plate of the two keg halfshells is at least partially removed to form an aperture for receiving avalve and spear for filling into and dispensing from the keg thebeverage housed therein.
 78. The keg of claim 76 wherein the end wallportion of each keg shell has an annular rim extending about theperiphery of the end wall portion and adjacent to the cylindrical wall.79. The keg of claim 78 wherein the annular rim is adapted to support achime for orientating the keg in a home beer dispensing apparatus. 80.The keg of claim 74 wherein the end wall portions of the kegs each havea concave curvature relative to the cylindrical side wall and interiorof the keg.
 81. The keg of claim 74 wherein each of the keg half shellsare formed by deep drawing of a material selected from the groupconsisting of steel, stainless steel, and aluminum.
 82. A keg suitablefor containing a beer, the keg comprising two keg half shells eachidentically formed by deep drawing of a material selected from the groupconsisting of steel, stainless steel, plated steel and aluminum to havean end wall portion and a cylindrical side wall that extendssubstantially normal from the end wall portion; each end wall portionbeing formed with a raised annular collar and face plate extendingacross the collar to normally close the collar, the face plate of one ofthe two keg half shells being adapted to engage a cooling plate in heattransfer relation therewith and the other face plate of the two keg halfshells is at least partially removed to form an aperture for receiving avalve and spear for filling into and dispensing from the keg the beerhoused therein; and, the cylindrical side wall terminating in acontinuous side wall edge portion, the two keg half shells having theirrespective side wall edge portions placed in abutting relation with oneanother along a common plane that passes through a center of the keg,and the keg half shells being joined together along the abutting sidewall edge portions to form the keg.
 83. The keg of claim 82 wherein theside wall edge portions are joined by a weld.
 84. The keg of claim 82wherein the end wall portions of the kegs each have a concave curvaturerelative to the cylindrical side wall and interior of the keg.